In this project, we will look at how to build a portable capacitive touch piano with

an Arduino,

a Capacitive Touch Shield for Arduino using the MPR121,

a piezo buzzer,

copper foil tape with conductive adhesive (cut in the shape of piano keys),

all enclosed in a clear acrylic enclosure (ProtoStax for Arduino) with the capacitive touch keys stuck on its top surface. This makes it a nice compact little piano that you can carry out and jam with and code up new tunes!

Adafruit's 12 x Capacitive Touch Shield for Arduino uses the MPR121 to provide capacitive touch sensing for up to 12 inputs. Coupled with the Adafruit_MPR121 library that makes it easy to detect and respond to touches on copper foil tape cut in the shape of keys that represent the 12 semitones of an Octave.

You can also program in your own touch sequences ("Secret Keys" or key combinations) to play any random tunes that can include as many octaves as you like (limited only by the power of your ear to hear the notes, or your piezo/speaker to play it!).

For the output, Arduino's tone library plays the sound through a Piezo buzzer. You can also use a speaker - just remember to use a resistor with it to restrict the current to that which can be provided by the Arduino's pin!

Copper foil tape with conductive adhesive make up the piano keys. It is important to get copper tape with conductive adhesive as you are going to stick the tape onto the wire that's connected to the shield.

With ProtoStax for Arduino, not only does it fit any of a whole range of Arduino boards (from Uno/Leanardo to Mega/Due), but there was enough room to fit not one, but two Shield inside (with some minor adjustments) - giving you protection for your entire project and not just your Arduino, and giving you a finished-looking project that you can actually display and use!

Ok, let's dive right in! You can find the tutorial with complete instructions, link to the GitHub repository for the code as well as ideas for how to take the project even further at

While the board has a somewhat similar footprint to the other Raspberry Pi Model Bs (3B, 3B+, 2B, 1B+) with the same mounting holes, there are a few significant changes. Instead of the HDMI port of the other boards, we now have 2 micro HDMI ports that support 2 4k displays! Instead of the micro-USB power port, we now have the (infamous) USB-C power port (infamous because it has a defect, and has some limitations on (see The Raspberry Pi 4 doesn’t work with all USB-C cables for more details) which USB-C power supplies can work with your Raspberry Pi 4.

Additionally, they have also switched the positions of the USB and Ethernet ports. The Raspberry Pi 4 has USB 2 and USB 3 ports (2 each) and a Gigabit Ethernet port, as opposed to 4 USB 2 ports and Gigabit Ethernet port over USB 2 bus on the earlier model). But more importantly, from an enclosure viewpoint, they have switched the locations of the ports, so your older Pi Enclosure will not work with the Raspberry Pi 4! (Not to mention the USB-C power port, and 2 micro-HDMIs in place of the HDMI port).

But thanks to ProtoStax's modular design, only a couple of changes were required to support the new Raspberry Pi 4s with the ProtoStax for Raspberry Pi B+ enclosure (now appropriately renamed to ProtoStax for Raspberry Pi B+ / Model 4B! 😊). We've changed the port cutouts on one of the long side pieces to be able to accommodate both the 3B+ and earlier models, as well as the new Raspberry Pi 4. Additionally, we now include a new short side wall piece that has cutouts to fit the new USB and Ethernet port configurations of the Raspberry Pi 4.

What this means to you, the user, is that you can purchase a ProtoStax for Raspberry Pi B+ / Model 4B enclosure, and be able to use it for both older Model B/B+s, as well as the new Raspberry Pi 4 Model B! Talk about value for money! 😊

Of course, the enclosure will also work very nicely with other ProtoStax enclosures, allowing you to stack horizontally, or vertically, or both, and use the enclosure in different configurations to support your stage of prototyping!

If you're an existing customer that has purchased a ProtoStax for Raspberry Pi B+ enclosure, don't worry - we'll be sending you the modified long side wall and the new short side wall so you too can enjoy the upgrades!

Happy Making!

Sridhar (and the ProtoStax Team! 😊)

PS - Here is an Extended Family Photo - so that the other enclosures didn't feel left out! 😜

In today's project, we will look at how to build an Audio Visualizer (like a graphic equalizer display), that will put on a light show for you in time to your music, using an RGB Matrix Shield, a Spectrum Analyzer Shield and an Arduino Uno. We will, of course, put it in a nice ProtoStax for Arduino enclosure so that you can have a finished project that you can proudly display by your music system to have a nice light show of your music!

SparkFun's Spectrum Shield has two MSGEQ7 graphic equalizer display filters, so it can analyze both channels of your stereo input and give representations of amplitude of different frequency bands in the spectrum. We read this information using an Arduino, and then use Adafruit's NeoPixel Shield for Arduino, that has 40 RGB NeoPixels arranged in an 8 x 5 format, to display the frequency band/amplitude information using a variety of color schemes. The end result is an addictive color display that dances to your music! I could watch that for hours! 😊

With ProtoStax for Arduino, not only does it fit any of a whole range of Arduino boards (from Uno/Leanardo to Mega/Due), but there was enough room to fit not one, but two Shield inside (with some minor adjustments) - giving you protection for your entire project and not just your Arduino, and giving you a finished-looking project that you can actually display and use!

Ok, let's dive right in! You can find the tutorial with complete instructions and link to the GitHub repository for the code at

This is the first of the project related posts that I talked about in my last blog post.

In today's project, I explain how you can make your own Internet-connected Weather Station that will display your local weather on a 3-color ePaper display (the kind of display that you can find on a Kindle, except this one has 3 colors (Red, Black and White) instead of two).

I use a Raspberry Pi along with a weather API (Application Program Interface) from Open Weather Map to query the weather data for my local area, and display that information on the ePaper display using some nice fonts and icons and colors to make it interesting!

I put the whole thing in a ProtoStax for Raspberry Pi Enclosure, so that you have a finished project that looks great, that you can display on your coffee table or night stand and see the weather information for your location (or locations) of choice! In this example, I used a Raspberry Pi B+, but the ePaper HAT will fit a Raspberry Pi A+ as well, or even a Raspberry Pi Zero. We have you covered on all 3 counts with our enclosures.

What I would like to point about the ProtoStax for Raspberry Pi * enclosures are that apart from their utility and clean lines, they also have enough room inside for a HAT/pHAT/Bonnet, so it allows you to utilize your enclosure for projects and protect everything, not just your RPi!

Ok, let's dive right in! You can find the complete tutorial including instructions and link to code at

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https://www.protostax.com/blogs/news/projects-to-do-with-your-arduino-or-raspberry-pi-with-protostax2019-07-17T17:46:00-07:002019-07-17T17:46:41-07:00Projects to do with your Arduino or Raspberry Pi with ProtoStax!Sridhar Rajagopal
Greetings!

It has been a while since my last update, but we've been busy at work here at ProtoStax!

We have described to you how wonderful ProtoStax enclosures and the variety of uses and configurations that you can put them to. However, as they say, a picture is worth a thousand words. In our case, an example is worth a thousand words. Plus, they are also fun, useful and educational to boot!

Keep watching this space for project based examples you can do with your Arduino or Raspberry Pi (or other MCUs that we will support as time goes by!) We will try to do full tutorials and all the instructions and code, and we'll also give you pointers and suggestions on how to take the project further! You know what they say about "giving a man/woman a fish vs. teaching a man/woman to fish" - we believe that the latter is always better in the longer run, but we'll also try to provide as much support as we can!

We've also created a GitHub account and will be hosting all of our examples there - check it out at https://github.com/protostax . We already have a couple of examples at the time of writing this.

The next blog posts will describe each of the projects, as well as new ones that we conceive of. All project related blog posts will be tagged as such, making it easier for your to find them!

Last May, I was preparing for my presentation at Maker Faire Bay Area 2018 - "Easy Energy Monitoring with Arduino and Dr. Wattson." I'd created a prototype that could collect and log data from my energy monitoring board to an SD card in CSV format for later analysis, initiated by the press of a button.

As I was adding my finishing touches and adjusting the AC wires for the load to be measured, the inevitable happened ...

Last May, I was preparing for my presentation at Maker Faire Bay Area 2018 - "Easy Energy Monitoring with Arduino and Dr. Wattson." I'd created a prototype that could collect and log data from my energy monitoring board to an SD card in CSV format for later analysis, initiated by the press of a button.

As I was adding my finishing touches and adjusting the AC wires for the load to be measured, the inevitable happened - the breadboard that had all my components slid off the end of the table but thanks to the lucky mess of wires, it didn't fully disconnect but was instead left dangling. I was able to salvage it and carefully inspect and reconnect any wires that were pried loose, both from my breadboard and also from my Arduino which was another piece of the puzzle that I had to manage. I'm sure this story sounds all too familiar to you - if not, then count yourself lucky (and maybe buy a lottery ticket)! 😊

Here are a few other prototyping "adventures" that I've had that you may be able to relate to:

How many of you have used a piece of plywood to lay all your components out together just to have them mounted on "something?!"

My Raspberry Pi enclosure looks lovely and has great protection! Everything else around it that it is connected to? - umm, not so much!

I have used molded plastic enclosures to put my finished prototypes in. There were some mounting holes and cutouts that I had to do, and I'm not the greatest at doing those with a professional finish. At the end of it, I had a pretty ugly enclosure, and man, was it difficult mounting and squeezing everything in there - AND, because there was only one opening at the bottom, final assembly was anything but easy! I did end up cracking at least two OLED displays in the process.

I have also 3D printed some enclosures. That's when I really got to understand the adage "Measure twice, cut once!" Any mistake in measurement or even the most minute of changes meant another 3 to 4 hours of 3D re-printing for even a relatively smallish enclosure.

My own meandering prototyping experiences were the inspiration, and also the itch that I had to scratch, leading me to create ProtoStax! ProtoStax has also evolved, going through more than 20 iterations over a period of time before I was finally satisfied to unleash it!

The following thoughts were at the forefront when creating ProtoStax:

It had to look good, of course! 😊

In order to protect any surfaces and to raise the platform to offer airflow and cooling, it had to have removable rubber feet--why removable? Hold on to that thought...

It had to support different stages of prototyping - when starting out, having open access to the board, but still having it mounted firmly on a platform is essential. Later on, it would be ideal to be able to easily add the other sides of the enclosure and have a fully enclosed project that also has room for a shield/HAT or two, or some user interaction components. Yet other projects require more airflow or open access - for example, just having the top and skipping the side walls, keeping them open.

I wanted all the sides of the enclosure to be individually accessible and modifiable. This modularity would also help support different stages of prototyping.

I wanted to have the ability to combine different enclosures together to make a bigger whole, for those situations where one enclosure is just not enough. [By keeping the rubber feet removable, an enclosure/board can be reconfigured to be stacked on top of another enclosure - in this configuration, it wouldn't need any feet, thereby making protective feet that aren't stuck on but removable a great option.]

Being a stickler for detail, an emphasis on things like cutouts for cable management, tapped screw holes, and so on would not be an afterthought.

The end result is ProtoStax, a Stackable Modular Enclosure System for all stages of your prototyping. Think of it as a LEGO/Meccano set for enclosures! It can be assembled with ease, support different configurations by adding or removing blocks, and also allow for different units to be combined together to make a bigger whole - form follows function!

We are starting off with supporting Arduino, Rasberry Pi and Breadboards, all in attractive clear acrylic enclosures that can proudly show off your electronics. We also plan to add other boards and finishes as we go along...stay tuned!

Please check out our main page for more information, or better yet, get yourself a ProtoStax enclosure and play around with it - you'll be pleasantly surprised, I promise! And stay in touch, sign up for the newsletter, etc., to keep abreast of developments. We would also love to hear about your enclosure stories and any requests you may have!

Here’s to getting your prototype groove on with ProtoStax to help you every stackable step along the way…happy Making!

Sridhar Rajagopal (and the ProtoStax team!)

PS: I did another presentation at this year's Maker Faire Bay Area 2019. This time, I used a ProtoStax prototype-based enclosure for my demo...looks much better than the image at the very top, doesn't it?! 😊